Yarn severing device for a circular knitting machine



Aug. 20, 1963 G. BILLl ETAL 3,100,976

YARN SEVERING DEVICE FOR A CIRCULAR KNITTING MACHINE Filed Feb. 15. 1961 Z 7 5 FIG] United States atent 3,100,97 6 YARN SEVERING DEVICE FOR A CIRiIULAR KNITTING MACHINE Giorgio Billi, Viale Torricelli 23, and VlIllClO Lucin, Via Lavilla 179, Galceti-Prato, both of Florence, Italy Filed Feb. 15, 1961, Ser. No. 89,501 Claims priority, application Italy Feb. 16, 1960 6 Claims. (Cl. 66-145) According to the invention there is provided a circular knitting machine havinga device for severing yarn with: drawn from the feed position, said device comprising a stationary cutting edge and a driven wheel having anonoircular cutting edge cooperating with said stationary cutting edge.

3,100,976 Patented Aug. 20, 1963 2 move in succession in contact with the edge 8a, each form therewith a pair of scissors, the contact point of the cooperating edges 8a, 12 moving towards the yarn as the scissors close. The wheel 11 projects slightly below the cutting edge 8a of the stationary projection 8. A spring 13 on the shaft urges the shaft axially inwardly so More particularly, the present invention provides a circular knitting machine having a device for severing yarn withdrawn from the feed position, said device comprising two cooperating cutters, one of which is stationary and has a cutting edge, extending substantially tangentially to a cylindrical surface defined about the rotary axis of the machine and containing the edge of the cover which overlies the needle cylinder, said edge extending adjacent said drioal surface and having a non-circular peripheral cutting edge, said wheel being rotated to cooperate with the stationary cutting edge in a substantially continuous scissors action to sever yarn presented betweenusaid cutting edges. t

Upon raising the yarn guide, the device severs the yarn closely adjacent the last stitch formed by the yarn thereby avoiding subsequent cutting of the yarn end by hand and oonsequenthandling of the fabric); a a

The invention willbe better understood from the following description and the accompanying drawing, which set forth one embodiment of the invention.

FIG. 1 is a diagrammatic axial sectional view of a circular knitting machine showing a yarn severing device according to the present invention;

FIG. 2is a plan view of the machine of FIG. 1; FIGS. 3 and 4 illustrate two details respect-ively of the roller and the stationary cutting edge cooperating therewithin the yarn severing device.

As is diagrammatically illustrated in theaccompanying drawing, the circular knitting machine has a needle cylin- In the drawthat the inner side of the wheel 11 on which the cutting edges 12 are formed, is pressed into con-tact with the fixed cutting edge 8a.

The shaft 10 is driven through a pair of bevel gears 14, 15,the gear 14 being coaxial with and driven by the plate 5 and the gear '15 being on the shaft 10. Preferably the diameter of the gear 15 is less than that of the gear 14 so that the wheel 11 will rotate at a rotational speed equal to the rotational speed of the needle cylinder 1 multiplied by the step-up gear ratio.

7 The disposition of the cutting edge 8a, and the inclination thereto of the cutting edges 12, and thedirection of theirotation of the wheel 11 are such that as the yarn moves into the angle for-med between the opposed cutting edges it is gripped and severed thereby in a scissors movement while the fabric together with the last needle which has picked up theyarn before the interruption of the feed by the raising of the yarn guide, passes in front of the severing device in the zone A. As is seen in FIG. 3, the Wheel rotates in the direction f l whilst the fabric moves in front of the wheel in the directionjl. The yarn to be severed is located in theyconvergent zone 3 between the cut-ting edge 8a and the cutting edge 12 which is approaching the edge 80.

a The length cfya-rn between the "severed end and the yarn guide-is retained by a device provided in the cover 5 of the "needle cylinder. This device may comprise a pneumatic nozzle 16in FIG. 2, which is extended in the horizontal direction adjacent the path of movement of arrow f1, the point of contact of each cutting edge 12 der 1 supporting needles 2 and yarn guides 3 are provided for feeding yarn to the needles. In thezone A where the stitch is formed and thus where the yarn is to be severed, a yarn severing device is located to sever said yarn coming from the yarn guide which has been raised to interrupt the feed. This device is located on the cover 5 of the needle cylinder which is above the rotary plate 6 carrying welt hooks. Plate 6 is rotated at the same rotational speed as the needle cylinder by a known form of drive.

The severing device comprises a projection 8 formed on a stationary ring 7, which is mounted on the cover 5,

the projection 8 being provided with a cutting edge 8a the periphery of the ring 7. The projection-:8 is extended outwardly and upwardly and the cutting edge 8a extends along substantiallylthe'whoie length of the projection.

with the cutting edge 8a is moved in the direction opposite to the arrow f2. For this purpose, the wheel 13 is formed with several steps defining teeth to provide several individual cutting edges as illustrated in the drawing, or the wheel 13 may be formed with a peripheral cutting edge having a single step. Alternatively, the cutting edge 12 may be formed with a number of steps or teeth, substantially greater than that indicated in the drawing.

The above description is given by way of example only, I

and numerous modifications thereto will be apparent to those skilled in the art which may be made without departing irom the invention as defined in the claims appended hereto Whilst cutting edges are referred to herein, no distinction is intended to be drawn between cutting and shearing, or between scissori-ng action and shearing action.

What we claim is: j

1. In a circular knitting machine having a rotatable needle cylinder-carrying needles to which yarnis fed and means for withdrawing yarn from the needles, a device for severing yarn withdrawn from the needles, comprising: a stationary cutting edge, a driven wheel having a Suitable supports 9 are=located on the cover 5 and form f bearings for, a substantially radial shaft 19. This shaft non-circular cutting edge'cooperating with said stationary cutting edge to cut the yarn withdrawn. from the needles, and means resiliently urging the wheel iaxially towards the axis of saidcylinder to press thenon-circular carries, at its outer end, a wheel 11 (see FIG. '3) formed with teeth similar to these of a. ratchet wheel. Each tooth has a radial edge'anda peripheral cutting edge 12 extending angularly to the radialedge. .These teeth, they needle'cylinder carrying needles to which yarn is fed and cutting edge into 2; In a circular knitting machine having a rotatable engagement with the stationary cutting edge. c

cutting edge means tor withdrawing yarn from the needles at a pre determined fixed position with respect to the cylinder, a

device for severing yam withdrawn from the needles at said position, comprising: cutting means having a stationary cutting edge, a rotatably driven wheel having a series of teeth, each of said teeth having a radial edge and a peripheral cutting edge angularly disposed to the radial edge and extending from the outermost point of the radial edge angularly inward toward the axis or the wheel, and means resiliently urging said Wheel axially inward toward said cutting means to engage the cutting edges of the teeth with the stationary cutting-edge as the wheel is rotated, whereby all yarns drawn between the stationary cutting edge and a peripheral cutting edge en-- 7 gaged therewithare instantly severed. g

- 3. A device according to claim 2, w herein the stationary cutting edge is longer than each of the peripheral cutting edges of the Wheel so that one of the peripheral cutting edges is always in engagement with the stationary 4. In a circular knitting machine having a rotatable needle cylinder carrying needles to which yarn is fed andmeans for withdrawing yarnjfrom the needles at a predetermined fixed'position with respect to the cylinder,

comprising: cutting two cooperating cutters, one of said cutters having a stationary cutting edge extending-in a plane parallel to another plane tangential to said cylinder and parallel to they axis of the cylinder, theyother cutter including a rotatahlewheel, means rotating the Wheel on an'axis perpendicular to the axis of the cylindensaid.

wheel having anon-circular peripheral cutting edge ex tending all around the wheel, and resilient means urging .5. In a circular knitting machine having a rotatable needle cylinder carrying needles to which yarn is fed and means for withdrawing yarn from the needles at a pre- 7 determined fixed position with respect to the cylinder,

cutters having a stationary cutting edge extending in a plane parallel toanother plane tangential to said cylinder 7 and parallel to the axis of the cylinder, the other cutter including a rotatable wheel, means rotating the wheel on an axis perpendicular to the axis of the cylinder, said wheel having a peripheral series of teeth, each of the teeth having a radial edge and a peripheral cutting edge angular-1y disposed to the radial edge and extending from I the outermost point of the radial edge angularly inward toward the axis of the wheel, and means resiliently urging said wheel axially inward toward said stationary cutting edge't-o engage the cutting edges of the teeth with the stationary cutting edge as the Wheel is rotated, said stationary cutting edge being longer than each'or'the peripheral cutting edges so that one'of the peripheral cutting edges is always in engagement with the stationary cutting edge, whereby all yarn drawn between'the stationary cutting edge and a peripheral cutting edge engaged therewith is instantly severed.

' 6. In acircular knitting machine having a rotatable needle cylinder carrying needlesto which yarn is fed and means for withdrawing yarn from the needles, a device for severing yarn withdrawn from the needles, -'comprising: a stationary cutting edge, a rotatablydriven wheel having a peripheral cutting edge cooperating with said stationary eutting'edge to cut the yarn withdrawn from J the needles, and means resiliently urging the wheel'axiat 1y toward the axis of said cylinder to press the peripheral cutting edge into continuous contact with the stationary:

cutting ,edge as the Wheel is rotated.

V UNITEDSTATES PATENTS g r 2,713,254 7 Minton July 19, 1955' 2,952,14 Rather Sept. "13, 1960 2,996,904 Stevens Aug. 22, 1961 

1. IN A CIRCULAR KNITTING MACHINE HAVING A ROTATABLE NEEDLE CYLINDER CARRYING NEEDLES TO WHICH YARN IS FED AND MEANS FOR WITHDRAWING YARN FROM THE NEEDLES, A DEVICE FOR SEVERING YARN WITHDRAWN FROM THE NEEDLES, COMPRISING: A STATIONARY CUTTING EDGE, A DRIVEN WHEEL HAVING A NON-CIRCULAR CUTTING EDGE COOPERATING WITH SAID STATIONARY CUTTING EDGE TO CUT THE YARN WITHDRAWN FROM THE NEEDLES, AND MEANS RESILIENTLY URGING THE WHEEL AXIALLY TOWARDS THE AXIS OF SAID CYLINDER TO PRESS THE NON-CIRCULAR CUTTING EDGE INTO ENGAGEMENT WITH THE STATIONARY CUTTING EDGE. 